


The One True King

by roe87



Series: Bucky as a D.C. heroine au [1]
Category: Captain America (Movies), Captain America - All Media Types
Genre: Action & Romance, Action/Adventure, Alternate Universe - Modern Setting, Alternate Universe - Royalty, Arranged Marriage, Atlantis, Bearded Steve Rogers, Bickering, Biracial Character, Biracial Steve Rogers, Brown Bucky Barnes, Bucky Barnes Feels, Bucky Barnes's Hair, Canon-Typical Violence, Enemies to Friends, Enemies to Friends to Lovers, Epic Battles, Fluff, Happy Ending, Humor, Jilted Bucky Barnes, Long Hair, M/M, Male Character of Color, Movie AU, Multiracial Character, Nomad Steve Rogers, POC Bucky Barnes, Post-Serum Steve Rogers, Quests, Reconciliation, Reunited and It Feels So Good, Royalty, Sea Monsters, Water, aquaman au
Language: English
Status: Completed
Published: 2019-10-29
Updated: 2019-11-11
Packaged: 2021-01-08 05:45:42
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 9
Words: 12,316
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21230774
Author URL: https://archiveofourown.org/users/roe87/pseuds/roe87
Summary: (Alternative title: The One True Thot)--Steve just wants to live out his life on the beach, despite being half Atlantean and of royal descent, and he almost gets his way...Then his once betrothed, Bucky, shows up out of the blue and demands Steve aid him on a quest to recover the lost trident of Atlantis.Steve agrees to help Bucky in his quest, and to defeat the power hungry Stark before he brings war to the Atlanteans and the surface world. And, Steve finds he enjoys being with Bucky again, and he willingly embraces his destiny as protector (Thot) of the deep.





	1. The surface world

**Author's Note:**

> Yes, hello, this happened. The Aquaman (movie) au no one asked for except me! Write the fic you want to see in the world.
> 
> So, a couple FAQs:
> 
> 1) No, you need not have seen the movie in order to read this fic, I've adapted elements of it for this story. (Although I do hope you watch the movie afterward, because it is my fave and it's really good!)
> 
> 2) Bucky and Steve are both POC in this, and I've moved the location from America in the movie over to the Mediterranean for this story. Bucky is brown skinned, while Steve is biracial/mixed race and a bit lighter skinned. This is my first time writing POC Steve/Bucky, and I'm doing it for myself and for my friends who want to see mixed and POC au's. If you don't like it, jog on. 
> 
> 3) I hope you enjoy this! :D 
> 
> \---
> 
> Thank you [Caribbeanblu](https://archiveofourown.org/users/caribbeanblu/works) for enabling me!
> 
> \---

_Jules Verne once wrote, 'put two ships in the open sea without wind or tide, and they will come together'._

Steve broke the surface of the water, flipping his shoulder length hair back and squinting in the early morning sun.

He'd come up in a small bay in the Turkish town of Bodrum. Looking left and right, Steve decided the beach was clear enough of tourists, and he waded out of the water dragging his long fishing bag behind him.

He only had on his board shorts on and a diving knife strapped to his leg; to any tourists who happened to notice him, he probably just looked like any of the other free diving fishermen who frequented the beach.

Steve dragged his heavy bag up the beach, to a group of young men he knew. They greeted each other in Turkish, a couple of the boys calling Steve words like merman and water spirit.

Steve smiled, and he traded in the goods he'd pulled from an old shipwreck for cash.

He had a big bar tab to pay off.

Steve waved goodbye and strode off down the beach. He was headed to his favorite beachside bar that overlooked the water. Tourists usually didn't go there, they stayed on the other beaches where all the newer bars and resorts were. Steve preferred the quiet anonymity of the locals.

He glanced out at the ocean as he walked by a tiny wooden pier. The sun was high in the sky now, glittering off the water. Steve smiled wistfully, and looked away to the beach.

When he heard a soft _thud_ come from the direction of the pier, Steve paused and looked back.

A figure now stood on the pier, silhouetted against the sun.

Steve did a double take and shielded his eyes to see. The figure was tall and built, probably about the same size as Steve, and wore a form fitting wetsuit.

The figure moved, walking up the pier toward Steve. The dark black wetsuit he wore glinted in the sunlight like shiny fishscales, and his entire left arm was covered in a metal armor that flashed in the light. The stranger had long dark hair, plastered down wet around his very familiar face.

Steve made a sharp intake of breath when he recognised the man scowling at him. _Bucky._

"Oh, no," Steve murmured, quickly turning about and trying to walk away.

"I've been looking for you," Bucky called after him.

Shit, Steve thought. Okay, so, unless he literally ran off, there was no getting out of this little reunion.

Steve plastered on a smile and turned around as Bucky marched toward him.

"Oh, hey," Steve said amiably. "I, uh, didn't see you there."

Bucky stopped right in front of him and glared. Bucky was good at glaring, Steve remembered, and he had very icy blue-grey eyes for doing it with.

"I'm here to ask a favor," Bucky said, his scowl fading. "I don't have anyone else to ask."

"Oh?" Steve said, and he couldn't help looking Bucky over. He looked good, and it'd been years since they'd last seen each other.

"I need to go inland," Bucky explained. "And I need a guide."

"Uh, sure," Steve said, though he wasn't sure at all. "I can find you a guide."

Bucky fixed him with another piercing glare. "Not someone else, Steve. I can't trust anyone else. It needs to be you."

"Why me?" Steve blurted out.

Bucky huffed, and held out a small glass bottle. "Because I'm searching for the lost trident of Atlantis, that's why."

"Ah, fairy tales," Steve mumbled, but he accepted the bottle anyway. Inside was an old piece of parchment, and he popped it out to take a look. "Nice map," he commented, smirking.

Bucky didn't look amused. "This is _important_, Steve. I need find this trident before I return to Atlantis."

"This _mythical_ trident," Steve corrected. "And what's in it for me?"

"Besides regaining your integrity?" Bucky snapped, eyes flashing blue. "You owe me."

Steve felt chastised at that. He supposed he did owe Bucky, since he'd practically jilted him.

"We were young, Buck," Steve tried. "I wasn't ready for marriage."

"Clearly you had more important things to do," Bucky said dismissively. "Does living like a surface dweller suit you?"

"Well, yeah?" Steve spread his hands. "I'm half human, you're not. You don't know what it was like for me down there. Other kids gave me a hard time."

"If you're expecting sympathy," Bucky replied, "look elsewhere. I have more pressing matters to attend to, like finding this trident."

"Oh, yeah?" Steve said. "And what will you do once we find this fairy tale trident?"

Bucky jutted his chin out proudly. "I'll challenge Stark for the throne."

"Uh..." Steve blinked in surprise. "What?"

"Will you help me or not?" Bucky pleaded.

Steve sighed heavily. "Alright," he agreed, and looked more closely at the map. "Where do we need to go?"

"To the land your people call the Sahara," Bucky said, pointing to a place on the parchment.

"Great," Steve muttered. "Well, we could swim it?" He gestured out at the water. "If we swim across the Mediterranean sea to Africa, we're practically there."

"Very well," Bucky said, and made for the pier. "Try to keep up," he said over his shoulder.

Steve chuckled, and jogged to catch up to Bucky's side. "I was the stronger swimmer," Steve reminded him.

"A lot's changed," Bucky said. They walked to the end of the pier together, and Steve replaced the parchment inside its bottle. He handed it over to Bucky, who gave him a small smile.

"Thank you," he said quietly.

Steve was taken aback, but he smiled too. "No problem. Let's go get your trident."

Bucky's smile turned into a smirk as he pointed his arms forward and dived cleanly off the pier.

Steve followed after him, diving into the water. The world above and all its noise disappeared as Steve was submerged, and though the waters were clear Steve's special eyesight kicked in, allowing him to see keenly.

Bucky's eyes too glowed under the water. "Ready?" he asked, angling into position.

Steve pointed himself in the right direction, and he nodded. Bucky made to swim forward, and Steve did the same: they both shot forward at high speed through the water together, breaking the sound barrier.

They had a lot of water to cover.


	2. The Sahara

On the African continent Steve and Bucky broke the surface and waded out of the water at the closest beach.

The waves were big, and they'd been swimming a long time. At one point Bucky almost dropped his bottle when a huge wave knocked into him. Steve reached over and took his elbow without thinking, to help steady him.

The look Bucky gave him when he snatched his elbow back was just short of murderous.

"Sorry!" Steve held his hands up. "Just trying to help."

They waded onto the beach, its sand hot from the midday sun. A few of the locals side eyed them curiously, but otherwise didn't bother them. It was lucky they'd come ashore on a quiet beach.

"First things first," Steve said, pointing to a tiny bustling market. "We need clothes to fit in."

"If we must," Bucky said, and they made their way over there.

Dry, and in civilian clothes, Steve bartered them a ride to a small landing strip on the fine desert sand.

All they needed now was to a plane headed in the right direction that Bucky's map indicated, and the best Steve could do was find a light aircraft carrying cargo.

They paid the pilot in gold coins, and jumped in the back along with all the crates and some chickens clucking. The plane took off, flying them west over the Sahara desert.

Bucky sat on a crate by a window, gazing out and clutching his stomach.

"You okay?" Steve asked, sitting on a crate opposite him.

"Never been this high up before," Bucky said, closing his eyes.

Steve nodded. "Yeah, it takes some getting used to." He couldn't help notice how long Bucky's hair had gotten, well past his shoulders now, and the dark waves looked so soft.

"So, uh," Steve started, trying for conversation now they had a minute, "what's new with you?"

Bucky opened his eyes and levelled Steve with a look. "If you're referring to my metal arm, it's a guard plate, as I injured my arm during training."

"No, that's not what I meant," Steve said. "I'm sorry. I just meant... in general?" He looked at Bucky pleadingly, as Bucky glared back at him. "Can we start again?" Steve asked. "How have you been?"

Bucky sighed and looked out the window. "What do you care."

"I... care," Steve said, which was the truth. He'd forgotten just how much he missed Bucky until Bucky was with him. They had grown up together, they'd been close... once.

"Look, Buck," Steve tried, "I'm sorry about backing out on the marriage, I really am. It's just... I don't think I'm the marrying kind."

Bucky side eyed him, so Steve went on.

"It wasn't you, it was definitely me." Steve indicated himself. "You see, I'm an asshole." He laughed weakly. "I'd make a terrible husband, and I'd make a terrible leader. Besides that, no one in Atlantis would accept me. As they all pointed out to me many times, I'm an outsider."

Bucky rolled his eyes at that. "There you go again. Always with excuses to step away from your responsibility."

"It's not an excuse," Steve argued, "it's the truth. I'm only half Atlantean. I was just a kid and I missed my mom, I wanted to come live with her."

"How is Sarah?" Bucky asked.

"She's good, she's fine." Steve nodded, then smiled wryly. "She, uh, she kept telling me to go check on you, at first. Still does, sometimes." Steve twiddled his thumbs in the silence. "How's your folks? Still together?"

Bucky exhaled quietly. "Yes, still together."

"And, um, they know you're looking for the trident?"

Bucky looked at Steve. "What do you think."

"I take it they don't," Steve laughed nervously. "So, what? They want you to marry Stark now? Isn't he a little old for you?"

"Ugh." Bucky pulled a face. "They've been trying to marry me off for years, and Stark's kingdom is now the strongest one. He wants to build an army, take over the remaining kingdoms and rule by dictatorship."

"Wait, what?" Steve couldn't believe it. "Why? I mean, I know everyone wants to be top dog, but why _now? _I thought Atlantis was all about democratic council?"

Bucky shrugged one shoulder. "The last few years... everyone's so angry, and there's been a lot of dangerous rhetoric. Many people believe that having only one ruler will help, and Stark thinks that should be him, but his policies aren't peaceful and he wants to smother democracy." Bucky looked at Steve, and he seemed sad. "I've never seen it this bad, Steve. There's too much hate."

"I see. Well, that sucks." Steve felt sad too. Hate didn't help anyone, Steve knew that. "So," he sighed, looking at the parchment again, "we find this trident, then what?"

Bucky's lips twitched in a smile. "I challenge Stark to a formal duel and I kick his ass, crown myself king and tell everyone to calm the fuck down."

Steve couldn't help smiling. Bucky hadn't changed, still the same Bucky with fire in his belly.

"I'll help you," Steve promised. "I won't let you down, Buck."


	3. The Deserter kingdom

After being dropped off by the plane in the middle of the actual desert, they trudged their way over sand dunes in the blazing hot sun while Bucky read the map.

"It's definitely here," he kept saying, holding up the map against the skyline.

"Yeah, are you sure about that?" Steve asked, feeling exhausted.

"The desert kingdom was here when this area was still an inland sea," Bucky explained. "When it dried up, they all got stuck and perished."

Steve huffed a laugh, kicking up sand with every step. "There's gonna be two more idiots perishing here today."

"They're the kingdom who forged the trident for King Atlan, the first king of Atlantis," Bucky said. "We're close, I know we are."

"Yeah, close to what, dying of thirst?" Steve retorted, surprised when Bucky turned back and jabbed a finger into his chest.

"Close to getting punched in the face," Bucky threatened.

Steve was amused to see Bucky so riled up, but it didn't change their current predicament. "Buck, look around." He waved a hand at the sand all around them. "We are _lost_. Hey, what's that over there? Oh, more sand. What a surprise!"

Bucky snorted, and turned away again. "You're the one who calls this mountain of dirt a home," he accused, marching off.

"I don't live in the desert!" Steve replied, jogging to catch up to him. "I live by the beach!"

"Oh, and that's so much better!" Bucky argued, throwing up his hands. "Beaches with pollution that pumps directly out into our seas. Oh, and you have these great big factories that puff out smoke into the air. You over fish the seas, and––"

"Okay, okay, point taken!" Steve said, moving in front of Bucky to get him to stop. "We got some idiots running the show, I agree! But we got some good stuff up here too. We have snowy mountains, and forests. And lakes! You'd like lakes," he insisted, "they're like little baby oceans."

Bucky gave him a flat look in reply, then raised the map to look at it again.

"Will you stop with that?" Steve snatched the map from Bucky's hands, and had all the intention of ripping it up right there. "This stupid thing is what got us lost," Steve said, taking one step back. The sand gave way beneath him and as Steve glanced down to look he got sucked in quicker than he could react.

He yelled as he went down, tumbling along a rocky chute, being battered this way and that. He must've been going at a rate of knots, and suddenly the chute ended and he was flung into mid air.

A dark cavern was far below him, with rocky outcroppings on either side. Steve flailed, managed to grab onto a piece of rock jutting out and pull himself up onto a ledge.

As if on cue, Steve heard yelling coming down the chute behind him. He had to smile: Bucky had followed him in.

Steve got ready, and when Bucky shot out from the chute into the air, Steve grabbed his hand. "Hold on!" he shouted, heaving Bucky up onto the ledge.

Bucky landed with a grunt, and they both lay there panting.

Steve glanced over to the side, to see if there was a way out, but what he saw was way more interesting: a passageway to some old ruins.

"Oh, hey," he said, grinning at Bucky. "Look what I found."

Bucky looked at him, incredulous. "What _you_ found?" he repeated.

"Uh huh." Steve grinned. "C'mon."

They picked themselves up and pushed through rock debris, having to jump down into the ruins of an ancient room or temple of some sorts. Steve looked around at all the relics, and the two huge statues of guards up ahead.

"So, this was the desert kingdom, huh?"

"Once upon a time," Bucky said, approaching a slab of rock on the ground. Steve approached too, eyes going wide as he saw the rock was a blacksmith's rock, but instead of a sword shape where the hot metal would've been poured, the shape was a trident.

Bucky smiled smugly at Steve. "Still think it's a myth?"

"Uh, well," Steve shrugged, "that's some pretty solid evidence, I guess." He looked around the room. "Where's the actual trident though?"

"We need to listen to the coded message," Bucky said, taking out the glass bottle.

"Oh, right," Steve muttered. He followed Bucky to a large circular rock in between the guard statues.

Steve watched as Bucky twisted the bottle and opened it up, then set it into small circular slots at the foot of the rock.

"Huh, like a puzzle piece," Steve said, then looked up at the rock expecting something to happen.

Bucky too, seemed confused. "Nothing's happening," he said, clearly disappointed.

"Well, yeah," Steve waved a hand dismissively, "all this tech's been sitting here since before the Sahara was a desert."

Bucky was quiet a moment, then said, "Since _before_ the Sahara was a desert."

"Thank you for repeating what I just said," Steve chuckled, then paused as Bucky approached him holding his hand up. "Uh, what are you doing?"

"Hold still," Bucky instructed, but Steve leaned away. "We need _water_," Bucky said, smiling. "And you're the closest source. Now hold still."

"Oh." Steve remained still as Bucky raised his hand and held it a couple inches from Steve's forehead. Steve watched as Bucky's eyes started to glow a bright blue, and he felt the sweat from his face and in his hairline run across his skin toward Bucky's outstretched hand.

Once he had what he wanted, Bucky slowly backed away, levitating the small drop of water in a blue glow. He directed the water onto the bottle, and the bottle lit up with swirls and old Atlantean writing.

The ancient machine it was in slowly whirred to life. Bucky smiled, the glow fading from his eyes. Steve grinned too, as he hadn't seen Bucky use his water powers for a long time.

"Show off," he said, as the machine powered up in front of them. "I could've just peed on it."

Bucky threw him a disgusted look, then the machine projected an image above them. Bucky gasped, and even Steve was impressed. "Who's that?" Steve whispered, looking at the old white guy holding a trident.

"King Atlan," Bucky hissed. "Ssh!"

"In this trident," said the projection, "resides the power of Atlantis. In the wrong hands, it would bring destruction. But in the hands of the true heir, it could unite all of our kings above and below. If you seek my power you must prove your worth. Journey beyond the edge of the world to the hidden sea. Look inside the bottle for the charted path. Only in the hands of the true king, can he truly see."

The projection disappeared, and Bucky stepped forward to retrieve the bottle. "We can't let anyone else find this," he said, then threw the bottle to the floor.

"Wait!" Steve tried, but the bottle smashed all over the floor.

Bucky looked at him in confusion. "What?"

"Shouldn't we have written all that down first?"

"I memorised it," Bucky said. "Didn't you?"

"Oh," Steve said, and cleared his throat. "Sure, I did too."

Bucky smiled slyly. "What'd he just say?"

Steve cleared his throat again. "He said, something something trident."

Bucky was about to reply when a small hatch opened near their feet, and they both jumped back with alarm. Steve took Bucky's hand, just to make sure he was okay. But they weren't under attack, it was just a compartment in the ground opening with something inside.

Bucky looked at Steve, then at their joined hands, and Steve quickly dropped Bucky's hand. "Sorry," he murmured, but Bucky didn't yell at him this time. Strangely, he seemed kind of quiet about it.

Steve figured they better get on with the next clue, so he bent down to look in the hatch and found another glass bottle.

"What is it with Atlanteans and bottles," Steve asked, popping the top and tipping out the contents. Another map.

Bucky unrolled it, and showed Steve the marked spot. "Italy," he said.

Steve had to laugh. "Guess we're headed back across the Med, then."


	4. Italy

**Notes for the Chapter:**

> Please note, as the tags say, some canon typical action/violence.
> 
> \---

After coming ashore in Sicily, dripping wet, they had to hitch a ride cross country to the cliffside town of Erice.

At least the sun was warm and they dried off pretty quick. Steve had never been to this particular province before but he had to admit it was beautiful: a small historic market town, with a pretty fountain in the town square amid the market stalls.

Bucky seemed very interested in all the bustling about of the market place, people going here and there and bartering in Italian. He watched people eating food at an open cafe, a curious expression on his face.

Of course, underwater in Atlantis all the food and customs were very different. Steve knew this from having lived there as a child. He watched as a woman at a flower stand gave Bucky a bouquet of pretty pink roses, and Bucky took them in quiet awe.

Steve smiled, and dug inside his slightly damp pocket for coins to pay the woman with.

When he turned back around, he saw that Bucky had bitten off one of the rose flowers and was eating it. Steve paused, looking at Bucky. He was about to point out not to eat it, but Bucky had such a delighted expression on his face that Steve couldn't bring himself to say anything.

Then Bucky offered the bouquet to Steve.

Oh, well, Steve thought. What was the harm? He carefully selected a stem and bit the flower off.

Bucky smiled at him happily, then took his bouquet and walked off through the square. Steve chewed on the flower, and it actually wasn't too bad. Fragrant.

Next they stopped at the fountain in the center of the square, with Bucky gazing down at the water.

Steve dug in his pocket and produced a coin, handing it over. Bucky took the coin, smiling at him, and held it over the fountain.

A young girl had appeared next to Bucky, looking up at him curiously. Bucky smiled at the kid, and offered the coin out.

She looked thrilled, and took the coin in her hand. She closed her eyes, clearly making a wish, then tossed the coin into the fountain.

Bucky subtly waved his hand and watery shapes of fish and seahorses leapt from the fountain, conjured by Bucky's special powers.

Steve saw the look of awe and delight on the kid's face, and the pleased smile on Bucky's face too. He had to smile.

When the kid ran off to go tell her mom about the magic fountain, Bucky stopped playing with the water.

"Looks to me like you're kinda enjoying this place," Steve commented.

"Well," Bucky said, his cheeks coloring. "I guess you were right about some places up here being pleasant."

Steve chuckled at that. "Yeah, this town seems very pleasant."

"We need to find the point on the map," Bucky said, glancing up at the sun. "We don't have a lot of time left."

They asked a couple of the locals, and were told the circle of statues printed on the map was up on the hill overlooking the sea.

So they made the climb, getting to the top of the hill and finding old Roman ruins there.

"Wow, check it out," Steve said, as they came to a circle of statues among the ruins. "This is what we're looking for?"

"I don't understand," Bucky said, looking at the ruins. "We need to find our charted path, so something here must tell us the heading."

"Look inside the bottle for the charted path," Steve recited, and held out his hand. "Let me see that bottle?"

Bucky handed it over, and Steve looked inside to check. Now that he was in the bright sunlight, he noticed something at the bottom. "Huh," he said, and pointed the bottle out to sea like a telescope. He closed one eye and peered inside: there was a charted map etched into the glass. "Neat."

"What? Let me see." Bucky took the bottle and looked into it, turning left and right to look at the horizon. "But how to do know where to point it?"

"Hm." Steve was looking at the statues, how they were all looking outwards from the circle. "Give me the bottle. What did the recording say again?"

Bucky handed him the bottle. "Look inside the bottle for the charted path. Only in the hands of the true king can he truly see."

"The true king," Steve repeated, and looked at the closest statue to him. He read the Roman letters at the base. "Marcus Agrippa. He was a great general but he wasn't a king." Steve moved to the next statue. "Neither was Scipio."

"How do you know all this stuff?" Bucky asked.

"My mom made sure I knew my history," Steve said, going around the circle of statues. "None of these guys are kings, except... this guy." He pointed to a half ruined statue. "Romulus. First king of Rome." Steve noticed that the statue's hand was up at his head, like he was looking out to sea. "Only in the hands of the true king can he truly see," Steve recited, gently laying the bottle into the statue's hand.

It fit like a glove.

Steve moved around the back, climbing up on the statue ruins carefully and peering over its shoulder to look in the bottle. "Hah! There it is," he told Bucky, pointing out to some islands in the distance. "That's our heading."

"Let me see!" Bucky scrambled up the statue, so Steve stood back to give him space. Bucky peered into the bottle, then looked out to sea. "We found it!" he exclaimed, then promptly slipped off the statue.

Steve reached out instinctively and caught him round the waist before he could fall. Now they were nose to nose, and Steve felt embarrassed. He made sure Bucky was steady on his feet before he let go, then he put some space between them.

"So, um." He smiled tentatively. "Not bad, huh?"

Bucky smiled back at him. "Not bad at all."

Steve's smile grew, and he was so busy gazing into Bucky's eyes that he didn't hear the incoming fire until it was too late.

"Bucky," he tried to say, as an explosion hit the ruins around them and blew up the statues. Both he and Bucky fell down with a grunt: unharmed but knocked off their feet.

"What the hell?" Steve coughed, scrambling up.

"They found me," Bucky hissed.

"What?" Steve gaped as Atlantean soldiers in full armored suits leapt onto the small hill, surrounding them. Their armor glistened in the sun and was powered by hydraulic water, their helmets all filled with water so they could breathe. They pointed their heavy hydro canons at Bucky. "Prince James of Atlantis," one of the guards spoke, his voice wobbly through an amplifier, "you are under arrest for high treason."

"Steve, run," Bucky hissed, looking at him worriedly. "I'll take care of this, meet me down by the dock."

"Are you crazy?" Steve said, and got to his feet. "I'm not letting these assholes push you aroun––"

Steve felt the full force of the hydro canon as it hit him in the chest, propelling him backwards.

"Steve!" Bucky shouted, as two of the guards flew up in their jetpacks and shot after Steve down the hillside.

Bucky scrambled up, aiming to follow them. A guard dropped down in front of him, pointing an Atlantean sword as he advanced.

"I order you to stand down!" Bucky told him, as the sword came dangerously close to his chest.

"Prince James, you are under arrest," the guard said. "Come quietly."

Two more guards landed behind Bucky, but he wasn't about to take this lying down. Bucky moved fast, pushing the sword out and moving in close to the guard to knock him down. Bucky wrenched the sword free and used it to fight, knocking back the guards and slicing off limbs, and smashing the hilt into their watery helmets.

They couldn't breathe on land, only the high-borns could. When their helmets were destroyed and the water drained away, they choked on air.

Bucky had the last guard restrained and was about to deliver a fatal blow, when the sword was shot out of his hand by a plasma rifle.

Bucky looked up to see more guards flying in, firing up their rifles, so he turned and ran under heavy fire.


	5. Escape

**Notes for the Chapter:**

> Canon typical action/violence, minor injuries briefly mentioned.
> 
> \---

Steve had managed to block the shot with his arms, and as he picked himself up off the ground he saw the skin on his forearms was red, blistered and smoking.

"Ow," he wheezed.

He was invulnerable to most human weapons, but Atlantean weapons not so much.

The two Atlantean soldiers landed on the ground in front of him, their heavy armor making a loud _thud_.

"I recognise you," the first guard said, his face barely visible in the watery helmet. "Half breed, abdicator. You should be dead."

"Well, sorry to disappoint," Steve said, getting to his feet. He looked to the side, spotting an old stone bench close by.

When the soldiers fired up their hydro canons and took aim, Steve grabbed the bench and hauled it up, using it as a shield when they fired.

The force from the canons blew up the bench and knocked him backwards, over the edge of the cliff face and Steve dropped through the air, limbs flailing.

Bucky ran from the soldiers across the tiled rooftops of the small town. They shot at him, red plasma energy exploding tile and brick around him.

He kept running, jumping across rooftops as he evaded their fire. He had no idea where Steve was but first he had to take out these soldiers, and he had no weapons here.

Bucky leapt across a small gap between the buildings, and as he was about to land on the next roof a shot knocked him flying and he crashed through the tiled roof instead.

He landed hard on the floor, coughing from dust. A soldier was on him almost immediately, grabbing him by the throat and hoisting him up.

Bucky struggled, feet kicking as he reached out to the soldier's helmet: with his metal hand, Bucky ripped at the circuitry there, and the soldier's helmet drained of its water.

The soldier dropped him, now choking because he couldn't breathe. Bucky coughed too, hand on his throat as he got to his feet. He'd fallen into some kind of store, and he was about to rush outside and search for Steve when he saw the remaining Atlantean soldiers drop down into the square outside.

Bucky backed away into the store. The sound of water dripping caught his attention, and he spotted some glass bottles that'd been knocked off their shelf in the fight: liquid was tipping out of them. Bucky realised that the bottles on every shelf in the store must be filled with wine.

The Atlantean soldiers aimed their plasma rifles and advanced on him. Bucky called upon his water power and moved his hands, feeling every drop of wine in the near vicinity: once he'd located all of the wine, he let out a scream and forced the liquid from its bottles, smashing them all. He formed the wine into spikes and pushed them through the air with his hands.

The soldiers were speared clean through, and knocked to the ground. Now they were dealt with, Bucky had to find Steve.

Steve had managed to hide from the soldiers on top of the town's bell tower, but as he peeped around it to see if they'd spotted him, a plasma shot was fired through the air.

Steve barely managed to jump free in time as the bell tower exploded, with the giant bell clanging loudly as it fell. Steve fell too, bouncing off roofs and onto hard stone, right in front of the town church.

"Ugh," he groaned.

People ran about the square in panic, screaming. Steve looked up as that bell clanged again, falling fast and right to where a child was standing there frozen in fear.

Steve heaved himself up and leapt, knocking his shoulder into the bell to bounce it off course. He saved the kid, and the bell slammed into a stone wall across the square.

Steve only had moments before those soldiers found him again, and he should've run but too many people needed his help. He called to them in Italian to get into the church and hide.

A voice called for help, and he found a couple stuck under a fallen bit of stone. Steve rushed over there and lifted it up, freeing them.

"Into the church," Steve told them, letting the stone down. "Hurry!"

The Atlantean soldiers dropped down behind him, and Steve felt a searing pain in his back as they lassoed him with plasma chains.

"Can't you give a guy a break," he bit out, turning round and yanking on the chains.

The soldiers may have been strong but they weren't a match for Steve. He pulled them into close quarters and punched them hard, doing damage to their suits.

"How'd you find us, huh," he asked, smashing the head of one soldier into the ground and holding him there by the throat.

The soldier sneered in reply. "Prince James is always being watched."

Steve growled, and smashed the soldier's helmet. This time it broke, and he choked as the water drained away.

The other soldier was on him then, stabbing Steve in the shoulder with an Atlantean steel sword. Steve cried out in pain and was forced onto the ground. He was trapped, wounded. But he wouldn't give up. He grit his teeth and kicked his leg out, knocking the soldier off balance and making him lose his grip on the sword.

It didn't stop him for long, but then the tip of a blade broke through the soldier's chest and he gargled in surprise. When the soldier dropped to the ground, Steve looked up to see Bucky behind him holding a sword.

"Steve!" Bucky dropped the sword and rushed forward, crouching down beside him. He carefully removed the blade from Steve's shoulder and applied pressure with his hand. "You're hurt."

"Bucky," Steve tried, close to passing out. "They're tracking you."

"What?" Bucky cradled Steve against him. "What did you say?"

"They're tracking you," Steve managed, before his eyes closed.

Bucky didn't understand, how could they be tracking him?

Unless...

Bucky looked at the decorative gauntlet on his metal arm. A gift, from Tony Stark.

Of course, Bucky thought: how could he have been so stupid?

Bucky held Steve gently in his lap, while he worked the gauntlet off his arm and smashed it onto the ground.

They had to get away from here, and fast.


	6. The kingdom of the trench

When Steve came to, eyes blinking slowly open, he saw fishing net and rigging above him against a golden sunset in the sky.

He sat up with a mild groan, realising he was on a small fishing boat. The gentle rocking of the calm sea was comforting. Steve looked down at himself to check his injuries, saw that he'd been stipped topless and had bandages of seaweed over his arms and chest.

Bucky must've done it, he thought, peeling the seaweed back from his shoulder to check himself.

All healed.

Surely whatever Bucky had done helped him heal from Atlantean inflicted injuries, Steve thought. He pulled off the rest of the seaweed and found a clean top laying nearby, so he pulled that on.

Someone was playing a melody: a simple yet pretty tune. Steve followed the sound to the bow of the ship, found Bucky sitting there on a crate playing an old wooden flute.

He stopped when Steve approached, looking bashful. "Surface instruments," he said, setting the flute down. "So unusual."

Steve smiled wryly, then gestured at the boat they were on. "Did you... steal a boat?"

"Are the boats at the dock not for public use?" Bucky asked, barely concealing a smirk.

"Uh, no." Steve chuckled. "Those belong to people."

"Huh," Bucky said, not sounding at all sorry about it.

Steve sat down close to him, looking Bucky over. He was a bit dishevelled, and had a dark bruise across one cheek. At least they'd made it out of there, Steve thought, relieved.

"Thank you," he told Bucky. "I had 'em on the ropes."

Bucky quirked a smile at that. "Of course you did," he replied. "Anyway, they're behind us now. It's what lies ahead we should be concerned about."

"Oh?"

"Our heading leads to the kingdom of the trench," Bucky said.

"Wait," Steve said, "isn't that the place full of sea monsters where Atlantis sacrifices people?"

Bucky nodded, and Steve groaned. He looked out at the horizon, with the sun setting across the water.

This was a bad idea, he thought.

"We should turn back," he said, looking to Bucky. "That's not a place we should be going."

"We can't turn back now," Bucky said firmly. "We've almost found the trident."

"Buck, there's no guarantee it exists," Steve told him. "I know you care about Atlantis and all, but this isn't worth it. If you want to get away from Atlantis, come live on land. I'll help you."

Bucky stared back at him, his expression unreadable. "Flee? Like you did?"

Steve sighed. "If I could do it all again, Buck, things would be different. If I'd known leaving you would give you all this trouble, I never would've left."

"But you did leave," Bucky said.

"I know." Steve looked at him, hoping Bucky could understand. "I was young, I was scared. Still am," he added with a small smile. "And I appreciate what you're trying to do, but I don't think it's worth getting yourself killed over. Come live on land with me, I'll look after you and you'll never have to worry about marriages again."

Bucky's eyebrows flicked up, curious. "Hm," he said. "Well, thanks for the offer, Steve, except we won't be safe on land either. Once Stark has a big enough army, he intends to invade the surface world."

"_What?_" Steve was shocked. "Why?"

"They're sick of the surface dwellers polluting the seas."

"Yeah, but... how would a war make that any better?" Steve argued.

"I know." Bucky rolled his eyes. "It's mostly an excuse to invade and be a dictator. I told you there's been unrest the last few years."

"Damn," Steve whispered, sitting back against the boat. He felt defeated, like their only choice to prevent war was to continue on this ridiculous quest for a trident that may or may not even be at the end.

"Steve," Bucky said gently, "it'll be alright. All I need to win the hearts and minds of the people, unite them, is the trident. Things can be set right again, they just need guidance."

"Alright," Steve agreed. "I said I'd help you, and I will. I just wish it didn't have to be this way."

They were quiet a moment, then Bucky said, "Will you come with me? When I challenge Stark?"

"And watch you kick his ass?" Steve grinned at him. "Of course I will."

Bucky smiled back. "You know, if you were to reclaim your birthright..."

Steve suppressed a groan. "Bucky," he tried.

"Reclaim your birthright," Bucky repeated, "then Stark would lose his following. You're the first in line to the throne."

"What makes you think the people of Atlantis would want me there?" Steve asked. "I don't fit in, I never did."

"If you think that being of two worlds makes you less worthy," Bucky said firmly, "you're wrong, Steve. It's exactly why you're needed right now. You could unite us all, stop the hate that keeps spreading."

"Buck, I don't know," Steve said. "Look, one step at a time, okay? Let's find your trident first. Get Stark out the way, then we can start debating politics."

Bucky's lips curved into a smile. "Alright. I agree to your terms."

Steve chuckled. "Okay. C'mon. Let's set the sails."

They sailed on as night fell, and the sea was as black as the night sky.

A storm blew in, with heavy rain and crashes of thunder. Steve climbed to the top of the boat to pull in their sails, protect them from the wind. He jumped down holding onto a rope, and started checking everything else was tied down securely.

Bucky had changed back into his Atlantean suit, with the extra armor on his left arm. He was on lookout, watching the water and checking they didn't crash into any rocks.

They were in deep ocean water now, far away from any land.

Steve grit his teeth as the rain battered him and flashes of lightning cut across the sky. He tied off a section of rope, focused on his task, when he spotted a dark shape at the corner of his eye.

Steve looked around, figured it was only a shadow. The dark shape landed on the side of the boat, and when it rose up to seven feet tall Steve realised it wasn't a shadow at all.

"Bucky!" he yelled, but Bucky was already there delivering a hard kick to the fish-like creature and knocking it back into the sea.

Steve ran over there carrying a harpoon, his feet slipping on the deck. Another shadow appeared behind Bucky, leaping over him.

"Bucky!" Steve shouted, watching as Bucky use his water power to create a wave and push the creature back.

Steve had almost reached Bucky when a creature tackled him down from behind. Steve wrestled with it on the deck, and as lightning flashed across the sky he got his first good look at it: some kind of mutant angler fish with large teeth and spiky fins.

Steve smacked the creature back with his harpoon, and the creature shrieked and roared. Steve was able to swing his harpoon round and knock the creature off the boat, back into the water.

Another bolt of lightning lit the sky and Steve happened to glance up: there were dozens of creatures clinging to the mast of the boat.

"Shit," Steve bit out, and hurried over to Bucky. "What are they?" he shouted over the wind.

"The trench!" Bucky shouted back. "We're here."

"Get in the cabin," Steve told him, as the creatures started to drop down onto the deck, baring their teeth. Steve and Bucky hurried into the cabin, shutting themselves in.

Steve abanoned his harpoon and searched for the boat's emergency flares. "If they're from the depths," he said, opening a box, "they won't like the light." He pulled out a flare and lit it, handing it over to Bucky.

Bucky brandished the bright red flare at the cabin's windows, scaring off the creatures one by one.

Steve stuck a spare flare into his pocket, then lit another for himself. The creatures were breaking into the cabin now, smashing the glass windows. "We can't stay here," he told Bucky.

"We have to jump!" Bucky shouted back, and began fighting his way through the creatures to get out.

Steve followed him, and outside there were creatures crawling all over the boat now. They stayed back because of the light of the flares, but they bared their teeth and claws, set to pounce any second.

Bucky went to the edge of the boat and Steve followed. The water below was churning in the storm, but they didn't have much choice. Bucky's flare went out, so that only left Steve's flare in his hand.

"Jump!" Bucky shouted, and they dived forward together.


	7. Kingdom of the hidden sea

Steve and Bucky propelled down through the water side by side, fighting their way through the creatures that came at them from all angles.

Steve brandished the flare and Bucky used his water powers to clear a path as they dived down the trench.

They must've swam miles, and when they finally reached the bottom Steve's flare had fizzled out. He quickly pulled out the spare and lit it, lighting them in a red glow under the water. The creatures pulled back from the light, and Bucky spotted an exit.

"Over there!" he said, pointing to a narrow cavern with light up ahead.

They swam forward together, using their Atlantean power to propel through the water and outswim the creatures giving chase.

Steve's flare died out fast, but they reached the crack in the cavern and made it out. On the other side was a bright blue and flashing electrical storm cloud, swirling violently in the water. The creatures wouldn't follow them out here.

"That thing will tear us apart!" Bucky shouted, as they stared at it.

"I don't think we have much choice," Steve replied, and offered his hand. "We'll go together!"

Bucky nodded and took his hand. They swam toward the cloud, trying to dodge lightning bolts. The strong current pulled them in, tossing them about.

Steve felt Bucky's hand ripped from his grasp, and he reached out as he tried to swim back to Bucky.

"Steve!" Bucky shouted, reaching for him too.

Steve pushed forward, almost touching Bucky's fingers with his. Then there was a blinding flash and they were ejected from the swirling cloud into still, deep waters.

Steve looked around frantically, and saw Bucky's figure up ahead in the water. He also saw the silhouette of a very large sea reptile coming toward them.

"Shit," Steve cursed, and propelled forward.

Bucky must've passed out, as he wasn't moving. Steve managed to hit the reptile just in time to knock its jaws away from Bucky, then he swam back and grabbed Bucky.

Steve swam toward the light, pushing to the surface. He didn't know where they were, and when they broke the surface he looked up at a giant open cave with jungle plants and enormous shining crystals hanging from its ceiling.

Winged dinosaurs flew through the air, screeching loudly.

Bucky spluttered beside him, and Steve pushed the wet hair from his face.

"What happened?" he asked, looking around.

"That must've been a portal," Steve said. "I don't know where we are."

"Oh." Bucky looked up as a giant pterodactyl passed over them. "This must be the hidden sea kingdom at the Earth's core."

Steve exhaled in amusement. "Of course it is." There was a beach up ahead, and Steve pointed to it. "Let's go over there. Get out of the water before we get eaten by that thing."

They swam to the beach, and walked onto soft white sand.

"What a weird place," Steve muttered, looking around. "Like Jurassic Park."

"There, look!" Bucky pointed, and jogged over to some stone ruins partially hidden by ferns.

Steve followed him, watching as Bucky pushed foliage out the way and read from whatever was on the stone. He looked up at Steve with a triumphant look. "It's here! This is the island of the kings, and the trident's final resting place."

Steve huffed a laugh. "Makes it sound like the trident was a living thing," he said.

"Well, it sort of is," Bucky said, getting to his feet. "Come on, we're close."

They followed a broken pathway of ruins into a glade, with bits of statue lying in pools of water covered in giant water lilies. A small, pretty waterfall lay beyond.

"Uh, hey, Buck?" Steve said, spotting a skeleton wearing an Atlantean suit of armor among the ruins. "This is where people got sacrificed, huh?"

"Yes," Bucky said. "And if they fought their way through the trench like we did and ended up here..." He looked around. "The trident is guarded by the Karathen, but I don't see it anywhere."

"The Karathen?" Steve's eyebrows hiked up. "The sea monster from fairy tales? Please don't tell me that's real too."

Bucky smiled at him, and shrugged. "The legend says the Karathen will only allow the one true king to pass. Guess we'll find out."

Steve groaned lightly, and followed Bucky as he picked his way over the ruins in the water, headed to the waterfall.

"I think we should have a strategy going in," Steve said, as they stood before the waterfall. "If there is something we need to distract, a dinosaur or whatever, I'll engage it while you get the trident."

Bucky nodded. "Alright. Be careful, Steve."

"I will." Steve smiled at him. "You too, okay?"

Bucky smiled back, and they stepped through the waterfall together.

On the other side was a deep pool, so they dived in. It was a long way down into a dark cavern. There were more ruins down here, clearly what'd been a great city once: very likely the old kingdom of Atlantis.

Steve spotted more skeletons in various armor, in a pile over by some rocks. Bucky touched Steve's arm, and pointed across the cavern. Steve looked, and there on a grand but old throne sat a skeleton in glowing armor, holding a shining gold trident.

It was _real_.

And more importantly, the trident was actually _here_. Steve was shocked to see it with his own eyes, and he glanced at Bucky. Bucky looked thrilled, and he grinned at Steve.

At least now Bucky had a chance to defeat Stark, Steve hoped.

Now it was down to business: Bucky indicated to Steve that he would go in first, and Steve was to hang back and cover him. Steve nodded, and got into position.

Bucky swam on ahead, slowly so as not to disturb the current and announce his presence to anything else in the cavern with them. He approached the throne cautiously but before he could get within arm's reach of it, the cavern shook.

Bucky paused, looking around to see what the threat was. Steve did the same, but he didn't know what was causing it: an earthquake?

The pillars of the ruins around them shook, dust and rubble dropping through the water. A deep rumbling shook the water, and a voice that reverberated off every corner of the cavern spoke to them:

_You do not belong here._

"Oh, boy," Steve whispered as the silhouettes of extremely large objects came through the water toward Bucky. "Buck, I think we found your sea monster."

_I have guarded the trident against false kings since the beginning,_ the voice boomed, _and for a thousand years._

"What is it?" Bucky called to Steve, as they swam to each other for safety. They watched the silhouettes come closer, and their shapes became clear. Tentacles, giant ones.

"Shit," Steve muttered. "Okay, I'll engage, you go get the trident." Bucky looked at him like he was worried, until Steve said, "Go!"

They split up, Bucky heading for the trident and Steve for the nearest tentacle.

_I have seen the greatest champions try and fail_, the voice taunted. A tentacle swept out from the right and batted into Steve, smashing him into a stone pillar.

Steve grimaced in pain, the pillar crumbling around him. When he looked across the cavern he saw Bucky wasn't faring much better, a tentacle knocking him away from the trident.

_You dare come here to claim Atlantis's greatest treasure_, the voice snarled, as another tentacle smacked into Steve._ And you, a half breed!_

"Great, another elitist," Steve wheezed, and dodged a tentacle in a bid to swim to Bucky.

This creature was clearly formidable, and they'd need to retreat and regroup if they wanted to beat it.

"Bucky!" Steve shouted, swimming to him. Bucky was trying to swim around the tentacles, to get to the trident. There were just too many, and they were too strong and quick. Bucky got trapped under a tentacle as it pummelled him down onto the sea floor.

"No!" Steve shouted, propelling forward and smashing into the tentacle to get it off Bucky. "Don't you hurt him!"

_You will both perish_, the voice threatened.

"No, _you_ perish," Steve argued, punching the tentacle away. The voice only laughed at him, the sound rumbling through the water.

Steve helped Bucky up, who was looking at him curiously. "Steve, are you... _talking_ to it?"

"Huh?" Steve looked back at him. "Yeah? Can't you hear it too?"

"No, all I hear is rumbling." Bucky glanced at the trident then back to Steve. "The trident gives you the power to command the sea. If we get it, we can command this thing to stop attacking us."

"Buck, I don't know if that's gonna work," Steve said, as thick dark tentacles started winding around them. "Best chance we have of getting out of here alive is without the trident."

"We need it," Bucky insisted.

_You thought yourselves worthy_, the voice scoffed. _You thought yourselves kings? _One tentacle with a pointed end raised up, ready to flatten them both.

_You dishonor this place with your presence._

Bucky was going to get killed at this rate, and Steve wasn't about to let that happen. "Stop!" he commanded, holding out his hand. He forced his long unused power to the surface, willing the creature to understand him, to listen.

The tentacle paused just above them, and Steve dared to look up.

_You understand me_, the voice said, reverent now.

"I do," Steve replied, lowering his hand.

_No mortal has conversed with me since King Atlan_, the voice said. _Who are you?_

"I'm nobody," Steve said, and it was the truth. "I came here because I had no choice. I came here to save my home, and the people that I love. I came because that trident is their only hope, and if that's not good enough, then _screw you_."

"Steve," Bucky whispered at his side, and Steve conceded perhaps telling a giant sea monster to go screw itself wasn't the wisest choice.

But they hadn't been crushed by the tentacle yet.

_No one has ever freed the trident from Atlan's grip,_ the voice told him, as the tentacles slowly withdrew. _If he deems you unworthy... Well, I haven't feasted in aeons and I am famished._

The creature had backed off. Steve couldn't believe it.

"What did it say?" Bucky asked, looking to Steve.

"I, uh..." Steve glanced over at the throne. "It wants me to try and free the trident, I think?"

Bucky's eyes went wide. "Then you should try. I believe in you, Steve."

"Bucky..." Steve shook his head, full of doubt now. "I'm no king."

"Atlantis doesn't need a king," Bucky told him, touching Steve's arm, "it needs something greater than that."

"What's greater than a king?" Steve asked.

Bucky smiled at him. "A hero. A king fights only for his nation but you, Steve, you must fight for everyone."

With Bucky looking at him like that, Steve almost felt like he could do it.

He supposed he had to try. For Bucky's sake.

"Go on, Steve," Bucky said gently. "I'll be right here."

Steve nodded, and he turned away and swam over to the throne. The skeleton sitting there was clearly very old, but its grip on the trident looked pretty solid. Steve swam closer. The gold trident was pulsing gently, sending out little sonic waves through the water. Steve felt them, heard them. He reached out, his fingers closing around the trident.

The sonic pulses went through Steve peacefully: from the tips of his fingers, down his arms and into his body to the ends of his toes. He closed his eyes, feeling the weight of it.

His grip around the trident tightened, and Steve pulled it free from the king's grasp. He held the trident up, almost in disbelief, and watched as it pulsed stronger in golden bursts.

The skeleton of the king vanished in the water, and the shiny Atlantean armor he'd worn now swirled around Steve, melding onto him.

So, this was happening, Steve thought. He held the trident close, heeding its call, and centered himself. Using his special power, he closed his eyes and felt himself connect to every living sea creature in the water: he could hear them, and they could hear him.

What a trip.

When he opened his eyes again, he swam over to Bucky with the trident. Bucky smiled back at him.

"The one true king," he said.


	8. The one true king

Tony Stark gazed out the viewing window of his ship at the scene before him on the ocean floor.

If all went to plan, he would soon have the title of Ocean Master and command an army big enough to invade the surface world.

His ship was approaching the next kingdom Tony needed as an ally, and if they refused like the last kingdom did he would use force to make them an ally.

Rhodey, his commanding officer and trusted counsel, swam to his side. Tony turned a smile to him, hoping for good news.

"Well?" Tony asked, when Rhodey didn't speak immediately.

Rhodey shook his head. "The tracking on Prince James went dark, Tony," he said quietly. Both Rhodey and Tony glanced across to where James's father, King George of Xebel, was currently in strategic talks with the generals.

"Hm," Tony said, displeased. "Probably got himself killed on his little adventure."

Rhodey pulled a face. "The prince is more capable than you think."

"Save it, Rhodey," Tony told him. "If he shows up, I'll deal with him then. In the meantime, we have a kingdom to strong arm."

"Tony," Rhodey urged quietly, "I think you should reconsider this move. Wait it out. What are you gonna do if King George finds out you sent your soldiers after his son? And for all we know James got injured or killed by them."

Tony shrugged. "He brought it on himself, going against my orders like that."

"Tony, please," Rhodey tried, but Tony held up his hand.

"Enough. We must advance." He swam away, toward the generals and King George. "Have we agreed on a strategy?" he asked, impatient to get on with it.

"We have," King George addressed him. "The brine are powerful, savage brutes but a swift assault aimed directly at their leadership will turn the tide. Defeat the brine king, and you will command the greatest military might on this planet."

Tony grinned. "Today we unite our kingdoms," he promised George. "Tomorrow, we scorch the surface!"

They took up their armor and their weapons, moving out onto the open platform and into the water.

The combined armies of Atlantis, Xebel, and the fishermen kingdoms were behind Tony and Xebel's king, George was at his side. They mounted their sea creatures: great white sharks for Atlanteans, giant sea horses for Xebel, and the fishermen who were more merfolk than human had body armor.

Tony closed the lid of his armored helmet, and called to his troops, "Rise, Atlantis!"

They advanced on the brine kingdom: a people who had mutated into crab-like form. The human sized crabs were marching across the sea floor to meet them in battle, with larger giant crabs walking behind them.

Tony used the tech in his armored suit to project his voice out, calling to the brine king, "Surrender now, before you are defeated!"

The brine only roared back their response, and marched on.

"Well, I tried to warn them," Tony said, as Rhodey's shark swam into line beside him. Rhodey didn't look happy about going to war again, but he'd follow Tony anywhere.

Tony and his army forged on, and engaged with the brine kingdom. Atlantis had better tech: its floating man o' war sea vessels shot out plasma lasers at the giant crabs, while the submersibles attacked the crab-people army down on the sea floor. Tony pushed his shark through the battle, using his trident to knock crabs out his path.

When he found the brine king, Tony went in for the attack. He used a combination of his trident and the lasers in his suit to knock the king down and cut off his claw. The brine king sprawled on the ground, wounded.

Tony dismounted his shark and raised his trident above the king, but Rhodey and King George swam in behind him.

"No, Tony!" Rhodey shouted, as George said, "We need him."

Tony lowered his trident, still holding it over the crab king as the fighting went on all around them. "Join me or die," he said.

"You expect me to address you as _your highness?_" the crab spat back.

"Not your highness," Tony sniffed, "you may call me ocean master."

"You can take my army, you soft bellied slug," the crab king replied, "but you will never have my allegiance!"

"So be it," Tony said, and raised his trident for the killing blow.

Then the sea floor shook, like an Earthquake was upon them. The fighting stilled and the ground all around them started breaking apart in great cracks.

"What is this," Tony said, watching the cracks in the floor get bigger, with debris exploding through the water.

Perhaps an underwater volcano rising, he thought, as he watched a giant mountain of rock rise up ahead of them on the battle field. Soldiers were thrown through the water left and right, and everyone pulled back to get out of the way.

But it wasn't a volcano: with an almighty roar, a sea monster of colossal proportions rose from the rocks amid swirling black tentacles. The monster stood before them , opened its massive jaws and roared again.

And something on top of its head... Tony tapped on the side of his helmet to enhance his vision, zooming in on the sea monster.

There, on its head and holding a glowing gold trident stood Tony's arch nemesis: the first son of Atlantis.

And Prince James was with him.

"Is that... _the Karathen?_" Rhodey said in disbelief.

"Shit," Tony muttered. "Alright, change of plan," he said, and spoke into his comms. "Everyone attack, _now!_"

Riding a giant sea monster was pretty cool, Steve thought.

It looked like they'd got here just in time too, as a large army of Atlanteans and Xebeleans were attacking the brine kingdom at the border.

Steve and Bucky rode on the Karathen's head as she (she'd told Steve she was a she) used her tentacles and her claws to smash through all the ships attacking her. Then she swam over the battlefield and straight at the man o' war sea ships, destroying them too.

Plasma canons went off all around them in the water, firing red, blue and green. A shot came at them and Steve deflected it with the trident, but it still knocked them backwards off the Karathen.

Bucky used his water powers to push away the soldier's who'd gotten closest to them, clearing the water.

"Steve, there's too many casualties," Bucky said, swimming up to him, "we have to stop the fighting now. I'll find my father, but you must defeat Stark."

"What if I can't?" Steve asked, searching Bucky's blue eyes.

"Take him out of his element," Bucky advised. "Draw him up to the surface and fight him there. I'll back you up."

"Alright." Steve nodded. "I got this."

"I know you do," Bucky said, gazing into his eyes.

Steve smiled, and then Bucky leaned in and kissed him. Steve was surprised at first, but his eyes half closed and he kissed back.

When they pulled apart, Steve grinned dopily. "Uh, what was the plan again?"

"The plan is to not get killed," Bucky said, lips twitching in a smile.

"Oh, yeah," Steve said, as Bucky swam off at high speed. "Right..." Steve used the trident, centered himself and called forth all sea creatures to come to their aid.

He was able to call on the sharks and sea horses used as steeds too, knocking a lot of the Atlantean forces down. Steve grabbed a sea horse with no rider and got on its back, swimming across the open battle field in a bid to get Stark's attention.

It didn't take long: Steve spotted the man himself in his shiny armor and bearing his own trident, hurtling toward him in the water on a great white shark.

"Here we go," Steve said, and drove his sea horse up to the surface.

Bucky swam hard, using his water powers to knock soldiers away. He had to get to his father.

The soldiers fired at him, but Bucky spun through the water and used his powers to create funnels of air, directing the funnels at the soldiers so they couldn't breathe.

"Stand down!" his father shouted, rearing up on his sea horse mount. "Let him pass."

"Father," Bucky said, swimming up to him. "Please. He has the trident. I know you think this war is necessary, but Steve is king by our most sacred law. If you turn your back on that now then the Atlantis you're fighting for is already dead."

"It's true," a soldier nearby pitched in, "the half breed has the trident. He commands the sea."

Bucky's father nodded. "Then that half breed is your king."

On the surface of the water, half destroyed Atlantean war ships lay bobbing on the ocean waves.

Steve drove his horse towards the biggest ship, with Tony hot on his heels. He only just made it to the surface waters as Tony shot at him with a plasma canon.

Steve pushed his mount out the way and then leapt up, breaking the water and high into the air. He landed hard on the wet metal deck of a ship.

Tony shot out of the water next, flying up into the air with the aid of his powered armor.

"Well, fancy seeing you here," Tony's amplified voice said mockingly. He hovered airborn and took aim with his arm canon, but Steve stood his ground. He'd spotted a column of water shoot up from the sea, and he smiled wryly.

"Fancy seeing Bucky too," Steve said, as the column of water seized Tony in its grip.

Steve watched in amusement as the column threw Stark about, then smacked him down onto the deck of the ship.

Bucky broke the surface of the water, jumping onto the deck of the ship next to Steve while Stark was still picking himself up from the floor, pulling off his helmet to vomit out water.

Bucky's father, King George and more Atlanteans broke the surface, all eyes on them.

"In a combat of the kings," Bucky shouted loud enough for all to hear, "you fight fairly! No advanced armor, just you and your trident. Let the people bear witness!"

"We will bear witness," King George replied, taking off his helmet too. Rhodey, Stark's commanders and all the soldiers were watching too.

Bucky turned to Steve and touched his arm briefly. "Good luck," he said softly, before stepping off the deck and into the water.

Steve readied himself, circling Tony as the other man wiped his mouth and laughed wryly.

"That trident doesn't change what you are," he taunted Steve. "A half breed bastard. Atlantis will never accept you!"

Steve shrugged easily, and drew his trident up to prepare for combat. "Then by bloodshed does fate make known its will."

Tony snarled and got to his feet. He held his trident out and charged at Steve with a roar. Steve fought him off. It'd been some time since he'd practised with a trident, but he hadn't forgotten.

His trident seemed to want him to win, too: cutting through the air faster than anything, delivering swift strong blows that knocked the wind out of Tony.

They fought, tridents clashing. Tony was a seasoned fighter but he wasn't as skilled out of the water: Bucky had been right to lure him up here.

And Steve had one trick up his sleeve that water dwellers didn't have.

When he'd knocked Tony back, Steve held his trident in front of him and began turning it in his hands, calling up the water and creating a circle of magical water before him.

Tony looked on in confusion, then leapt in to attack.

Steve used the water shield to repel Tony's advance, and powered by Atlan's trident it was powerful enough to knock him to the ground. Steve didn't give Tony time to recover: he leapt, flipping upside down and thrusting with the trident as Tony held up his own in defence.

Atlan's trident won, and broke Tony's trident in two.

Steve landed on the deck, swinging back around and pointing the tip of his trident at Tony's neck.

"Finish it," Tony said weakly, staring back at him.

"Yield the throne," Steve said calmly.

"Mercy is not our way," Tony snarled.

"Maybe you haven't noticed, Stark," Steve said, "but I'm not one of you." He stood back, relaxing his trident.

He'd spared Tony's life, and Tony didn't try to get up and challenge him again. Atlantean soldiers marched out of the water and onto the deck, with Bucky and King George leading the way.

"Take him," Bucky commanded. "But make sure he has a view."

Steve watched as Stark was put into restraints. As they led him away, Steve said quietly, "Stark, when you're ready? Let's talk."

Tony looked back at him in bewilderment as the soldiers took him away, to the water's edge where a wave enveloped them and they were gone.

"People of Atlantis!" Bucky called out, addressing everyone still watching from the water. "Today began in bloodshed, but let it end up in joy." He gave Steve a side long smile as he indicated grandly to him. "I give you, King Steven!"

"Hail to the King!" Bucky's father called, directing his subjects to join in.

"Hail to the King!" came the cheers from the sea.

Steve just gripped his trident and smiled awkwardly as Bucky came in close. "So," he whispered, "what do I do now?"

Bucky smiled fondly at him. "Be their king."

"Ooh, this is gonna be fun," Steve said, and gave into his impulse to lean in and press a kiss to the side of Bucky's head, hair damp from the water.

Then he raised his trident high in the air and shouted, "To Atlantis!"

The Atlanteans cheered in response, and in the distance the Karathen broke the water with a mighty roar, joining in the cheer.

**Notes for the Chapter:**

> Please enjoy this gorgeous commission of Bucky and Steve I requested from artist [mma_mookie](https://twitter.com/mma_mookie) on twitter. Go check them out! :D
> 
> ~~
> 
> (Fun fact: the Karathen in the movie is voiced by Julie Andrews!)


	9. Epilogue

"And these are your royal chambers," Bucky was saying, as they swam through the palace halls.

Steve remembered the palace, but he'd never been behind the scenes in the royal chambers like this.

"All your diplomatic visitors will come via the main hall," Bucky explained matter of factly. "You'll receive them publicly then take them into the king's chambers for private counsel."

Steve wasn't really listening, too busy gazing at Bucky: he had a tiara on, a simple silver band that pushed his hair back from his face, with Xebel's red starfish emblem in its center. Bucky's long hair floated behind him in the water, and he'd never looked more beautiful to Steve.

"There's a concealed passage to the throne room here," Bucky said, pressing a shell in the wall. The panel slid away, and he swam through. Steve followed him, coming out on the enormous open throne room of Atlantis.

He remembered this room, but he'd last been here as a kid. It was still as grand and intimidating as it'd been then.

At least the room wasn't full: only a few of the royal guards swam on patrol at the far end of the room. The empty seats of the counsel and the audience were to either side of the large shell shaped throne.

"My parents and the fishermen royals will be the first to visit," Bucky went on. "You'll receive them here. It's important to lay down a peace treaty immediately, and extend that to the brine kingdom."

"Mm," Steve said, looking at Bucky with a smile.

Bucky eyed him closely. "Steve, are you even listening?"

Steve grinned back. "Peace treaty, play nice. Got it."

"This is important," Bucky insisted. "We must bring peace to the kingdoms after what Tony tried to pull."

"Well, why don't you take over negotiations?" Steve replied.

Bucky looked taken aback. "I can't speak for the king."

"Sure you can," Steve said.

"_Steve_." Bucky huffed. "There's a protocol. I'm from Xebel, not Atlantis."

"Yeah, but... you're gonna help me, right?" Steve asked, looking Bucky in the eyes. "I can't do this without you, Buck."

"You have advisers already," Bucky said, "but I will also advise you."

"I'm not talking about that." Steve reached out, taking Bucky's hand. "I thought... you know?"

"Know what?" Bucky said, as Steve pulled him closer. "You want me to be your consort?"

Steve broke into a grin. "I love it when you talk official."

Bucky smiled too, seeming shy. "Steve... are you sure that's what you want?"

"I just want you," Steve said softly, tipping Bucky's chin up with his finger. "If you'll have me."

Bucky searched his eyes, and Steve gazed back into sparkling blue. Then Bucky leaned in and kissed him passionately.

Steve kissed him back, closing his eyes. Now they weren't in the middle of a battlefield, Steve could relax and lose himself thoroughly in the kiss.

Until someone cleared their throat.

They broke apart, and Steve looked round to see Natasha and Rhodey, royal advisers to Atlantis, floating there watching them. Natasha was smiling like she was pleased, but Rhodey rolled his eyes.

"If you're quite done," he said dryly, "we have a few matters of state to attend to."

"Yeah, yeah," Steve replied, stifling a laugh. "No time for fun. I'll make a note."

"Glad to see you two finally worked things out," Natasha said.

"We, um, well, we," Bucky spluttered.

He seemed shy about it, so Steve stepped in. "We'll do our best, Nat. In the meantime, as far as Atlantis is concerned, Bucky's going to join in the whole royal duties, advising thing." Steve waved his hand vaguely. "All that official stuff. He and I are a team. A package, if you will."

Bucky looked at him in surprise, while Rhodey raised an eyebrow. "Right," Rhodey said. "Well, we need to set up the first audience with the king, if that's alright with you both?"

Steve smiled, and he looked to Bucky as he offered his hand. Bucky took his hand, and smiled back at Steve.

"Okay," Steve said, "we're ready."

**Author's Note:**

> Thanks for reading! Kudos and (nice!) comments fuel me!
> 
> Here is a [rebloggable post on tumblr](https://jro616.tumblr.com/post/188686096925/the-one-true-king-chapter-1-roe87-captain).
> 
> Here is the Steve/Bucky fanart by mma_mookie [on tumblr](https://jro616.tumblr.com/post/189001044450/jro616-stevebucky-aquaman-movie-au-read-the) and [on twitter](https://twitter.com/jro616/status/1193872776953835520?s=19).
> 
> Me: [tumblr](http://jro616.tumblr.com) and [twitter](https://twitter.com/jro616).
> 
> Feel free to come yell at me esp if you like Aquaman too!


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